The present disclosure generally relates to cover systems, and more particularly relates to a gliding pivot for a cover system.
Cover systems for trucks are widely known. Such systems can use bows or arms having stationary or movable pivots for extending a flexible cover, or tarpaulin, over the open top of a container body. Roll-off container trucks, however, present special problems for cover systems. In particular, such container trucks tend to have differently sized beds, and are required to accept containers of different dimensions. To accommodate these variances, the arms normally used in conventional truck bed covers have to be long enough to reach from their mounting point to both the front and rear ends of the truck bed, regardless of the overall length of the bed. U.S. Pat. No. 5,292,169 shows one typical prior truck container cover system in which the cove system is limited to a particular length. Such cover systems are not able to efficiently accommodate containers of different sizes. Newer cover systems have developed that incorporate a sliding pivot for the cover bow, such as the system disclosed in U.S. Pat. No. 6,257,464 to Searfoss, the entire disclosure of which is incorporated herein by reference. In systems of this type, the pivot point for the cover bow can be shifted along the length of the vehicle.
FIG. 1 shows one example of a cover system 10 for a hauling truck T. The cover system includes a cover assembly 12 that includes a flexible cover mounted on a roller on which the cover is rolled in a stowed or retracted configuration and from which the cover is extended. The flexible cover is carried by a pair of bail arms 14 mounted on opposite sides of the vehicle frame F, with the bail arms and cover sized and configured to span the length of a container carried by the hauling truck. The bail arms thus straddle a container rolled onto the frame F. Each bail arm can include a lower arm 15 and an upper arm 16 connected by a knuckle pivot 18. The lengths of the bail arm segments are calibrated to be able to extend the cover over the entire roll-off container while maintaining the cover in sufficient tension in the open position.
The bail arms 14 are mounted at a pivot mechanism 20 to a sliding mechanism 22. The pivot mechanism 20 includes components to exert a torque on the bail arms to pivot the arms from the closed position shown in FIG. 1 to an open position spanning the open top of the roll-off container. The sliding mechanism 22 is configured to slide the pivot mechanism in the longitudinal direction 24 relative to the vehicle frame F as the pivot mechanism 20 pivots the bail arms. This feature allows the bail arm to span the length of any container supported on the frame.
Sliding pivot systems are often cumbersome and difficult to control. There is a need for an improved sliding pivot cover system that can accommodate containers having different lengths and that provides for smooth extension and retraction of the flexible cover.